More than 80 percent of the decline in violent crime was attributed to a plunge in simple assaults, by 15 percent. Those assaults accounted for nearly two-thirds of all violent crimes in 2010.

The combined total of property crimes and violent crimes was down 6.6 percent last year, from 20 million to 18.7 million.

The numbers come from the National Crime Victimization Survey, which gathers information on nonfatal crimes against people age 12 or older by questioning a nationally representative sample of U.S. households.

Turning to rates of crime per thousand residents, which takes into account population growth over time, it's clear that the decline in violent crime is part of a long-term trend that began in 1993.

From 1993 through 2010, the rate of violent crime has declined by a whopping 70 percent: from 49.9 violent crimes per 1,000 people ages 12 or older to only 14.9 per 1,000 in 2010.

Blumstein added that "the victimization survey is basically confirming" the FBI's preliminary figures from last May on crimes reported to police during 2010. That early, incomplete FBI data showed reported crime fell across the board last year, extending a multiyear downward trend with a 5.5 percent drop in the number of violent crimes in 2010 and a 2.8 percent decline in the number of property crimes. The FBI's final figures for last year will be released Monday.

The victimization survey figures are considered the government's most reliable crime statistics, because they count crimes that are reported to the police as well as those that go unreported.

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